For presenting information visually, a computer display may include an optical system. A computer input device may also include an optical system for detecting user input. In various ways, computer display and input devices have been integrated in the form of multifunction components. One such example is an optical touch-screen, where user input is detected optically and is guided by context-dependent graphics appearing on the screen.
In some cases, practical construction of relatively small-footprint optical systems for display and/or input devices presents a challenge because of the stiff dimensional constraints inherent therein. The light-guiding approaches of traditional optical engineering may, in these devices, be difficult to scale down to provide satisfactory display quality or input functionality.